drivers/i2c/i2c-core-base.c

   1 /*
   2  * Linux I2C core
   3  *
   4  * Copyright (C) 1995-99 Simon G. Vogl
   5  *   With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi>
   6  *   Mux support by Rodolfo Giometti <giometti@enneenne.com> and
   7  *   Michael Lawnick <michael.lawnick.ext@nsn.com>
   8  *
   9  * Copyright (C) 2013-2017 Wolfram Sang <wsa@the-dreams.de>
  10  *
  11  * This program is free software; you can redistribute it and/or modify it
  12  * under the terms of the GNU General Public License as published by the Free
  13  * Software Foundation; either version 2 of the License, or (at your option)
  14  * any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful, but WITHOUT
  17  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  18  * FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
  19  */
  20
  21 #define pr_fmt(fmt) "i2c-core: " fmt
  22
  23 #include <dt-bindings/i2c/i2c.h>
  24 #include <linux/acpi.h>
  25 #include <linux/clk/clk-conf.h>
  26 #include <linux/completion.h>
  27 #include <linux/delay.h>
  28 #include <linux/err.h>
  29 #include <linux/errno.h>
  30 #include <linux/gpio.h>
  31 #include <linux/i2c.h>
  32 #include <linux/idr.h>
  33 #include <linux/init.h>
  34 #include <linux/irqflags.h>
  35 #include <linux/jump_label.h>
  36 #include <linux/kernel.h>
  37 #include <linux/module.h>
  38 #include <linux/mutex.h>
  39 #include <linux/of_device.h>
  40 #include <linux/of.h>
  41 #include <linux/of_irq.h>
  42 #include <linux/pm_domain.h>
  43 #include <linux/pm_runtime.h>
  44 #include <linux/pm_wakeirq.h>
  45 #include <linux/property.h>
  46 #include <linux/rwsem.h>
  47 #include <linux/slab.h>
  48
  49 #include "i2c-core.h"
  50
  51 #define CREATE_TRACE_POINTS
  52 #include <trace/events/i2c.h>
  53
  54 #define I2C_ADDR_OFFSET_TEN_BIT 0xa000
  55 #define I2C_ADDR_OFFSET_SLAVE   0x1000
  56
  57 #define I2C_ADDR_7BITS_MAX      0x77
  58 #define I2C_ADDR_7BITS_COUNT    (I2C_ADDR_7BITS_MAX + 1)
  59
  60 /*
  61  * core_lock protects i2c_adapter_idr, and guarantees that device detection,
  62  * deletion of detected devices, and attach_adapter calls are serialized
  63  */
  64 static DEFINE_MUTEX(core_lock);
  65 static DEFINE_IDR(i2c_adapter_idr);
  66
  67 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver);
  68
  69 static struct static_key i2c_trace_msg = STATIC_KEY_INIT_FALSE;
  70 static bool is_registered;
  71
  72 int i2c_transfer_trace_reg(void)
  73 {
  74         static_key_slow_inc(&i2c_trace_msg);
  75         return 0;
  76 }
  77
  78 void i2c_transfer_trace_unreg(void)
  79 {
  80         static_key_slow_dec(&i2c_trace_msg);
  81 }
  82
  83 const struct i2c_device_id *i2c_match_id(const struct i2c_device_id *id,
  84                                                 const struct i2c_client *client)
  85 {
  86         if (!(id && client))
  87                 return NULL;
  88
  89         while (id->name[0]) {
  90                 if (strcmp(client->name, id->name) == 0)
  91                         return id;
  92                 id++;
  93         }
  94         return NULL;
  95 }
  96 EXPORT_SYMBOL_GPL(i2c_match_id);
  97
  98 static int i2c_device_match(struct device *dev, struct device_driver *drv)
  99 {
 100         struct i2c_client       *client = i2c_verify_client(dev);
 101         struct i2c_driver       *driver;
 102
 103
 104         /* Attempt an OF style match */
 105         if (i2c_of_match_device(drv->of_match_table, client))
 106                 return 1;
 107
 108         /* Then ACPI style match */
 109         if (acpi_driver_match_device(dev, drv))
 110                 return 1;
 111
 112         driver = to_i2c_driver(drv);
 113
 114         /* Finally an I2C match */
 115         if (i2c_match_id(driver->id_table, client))
 116                 return 1;
 117
 118         return 0;
 119 }
 120
 121 static int i2c_device_uevent(struct device *dev, struct kobj_uevent_env *env)
 122 {
 123         struct i2c_client *client = to_i2c_client(dev);
 124         int rc;
 125
 126         rc = acpi_device_uevent_modalias(dev, env);
 127         if (rc != -ENODEV)
 128                 return rc;
 129
 130         return add_uevent_var(env, "MODALIAS=%s%s", I2C_MODULE_PREFIX, client->name);
 131 }
 132
 133 /* i2c bus recovery routines */
 134 static int get_scl_gpio_value(struct i2c_adapter *adap)
 135 {
 136         return gpio_get_value(adap->bus_recovery_info->scl_gpio);
 137 }
 138
 139 static void set_scl_gpio_value(struct i2c_adapter *adap, int val)
 140 {
 141         gpio_set_value(adap->bus_recovery_info->scl_gpio, val);
 142 }
 143
 144 static int get_sda_gpio_value(struct i2c_adapter *adap)
 145 {
 146         return gpio_get_value(adap->bus_recovery_info->sda_gpio);
 147 }
 148
 149 static int i2c_get_gpios_for_recovery(struct i2c_adapter *adap)
 150 {
 151         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 152         struct device *dev = &adap->dev;
 153         int ret = 0;
 154
 155         ret = gpio_request_one(bri->scl_gpio, GPIOF_OPEN_DRAIN |
 156                         GPIOF_OUT_INIT_HIGH, "i2c-scl");
 157         if (ret) {
 158                 dev_warn(dev, "Can't get SCL gpio: %d\n", bri->scl_gpio);
 159                 return ret;
 160         }
 161
 162         if (bri->get_sda) {
 163                 if (gpio_request_one(bri->sda_gpio, GPIOF_IN, "i2c-sda")) {
 164                         /* work without SDA polling */
 165                         dev_warn(dev, "Can't get SDA gpio: %d. Not using SDA polling\n",
 166                                         bri->sda_gpio);
 167                         bri->get_sda = NULL;
 168                 }
 169         }
 170
 171         return ret;
 172 }
 173
 174 static void i2c_put_gpios_for_recovery(struct i2c_adapter *adap)
 175 {
 176         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 177
 178         if (bri->get_sda)
 179                 gpio_free(bri->sda_gpio);
 180
 181         gpio_free(bri->scl_gpio);
 182 }
 183
 184 /*
 185  * We are generating clock pulses. ndelay() determines durating of clk pulses.
 186  * We will generate clock with rate 100 KHz and so duration of both clock levels
 187  * is: delay in ns = (10^6 / 100) / 2
 188  */
 189 #define RECOVERY_NDELAY         5000
 190 #define RECOVERY_CLK_CNT        9
 191
 192 static int i2c_generic_recovery(struct i2c_adapter *adap)
 193 {
 194         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 195         int i = 0, val = 1, ret = 0;
 196
 197         if (bri->prepare_recovery)
 198                 bri->prepare_recovery(adap);
 199
 200         bri->set_scl(adap, val);
 201         ndelay(RECOVERY_NDELAY);
 202
 203         /*
 204          * By this time SCL is high, as we need to give 9 falling-rising edges
 205          */
 206         while (i++ < RECOVERY_CLK_CNT * 2) {
 207                 if (val) {
 208                         /* Break if SDA is high */
 209                         if (bri->get_sda && bri->get_sda(adap))
 210                                         break;
 211                         /* SCL shouldn't be low here */
 212                         if (!bri->get_scl(adap)) {
 213                                 dev_err(&adap->dev,
 214                                         "SCL is stuck low, exit recovery\n");
 215                                 ret = -EBUSY;
 216                                 break;
 217                         }
 218                 }
 219
 220                 val = !val;
 221                 bri->set_scl(adap, val);
 222                 ndelay(RECOVERY_NDELAY);
 223         }
 224
 225         if (bri->unprepare_recovery)
 226                 bri->unprepare_recovery(adap);
 227
 228         return ret;
 229 }
 230
 231 int i2c_generic_scl_recovery(struct i2c_adapter *adap)
 232 {
 233         return i2c_generic_recovery(adap);
 234 }
 235 EXPORT_SYMBOL_GPL(i2c_generic_scl_recovery);
 236
 237 int i2c_generic_gpio_recovery(struct i2c_adapter *adap)
 238 {
 239         int ret;
 240
 241         ret = i2c_get_gpios_for_recovery(adap);
 242         if (ret)
 243                 return ret;
 244
 245         ret = i2c_generic_recovery(adap);
 246         i2c_put_gpios_for_recovery(adap);
 247
 248         return ret;
 249 }
 250 EXPORT_SYMBOL_GPL(i2c_generic_gpio_recovery);
 251
 252 int i2c_recover_bus(struct i2c_adapter *adap)
 253 {
 254         if (!adap->bus_recovery_info)
 255                 return -EOPNOTSUPP;
 256
 257         dev_dbg(&adap->dev, "Trying i2c bus recovery\n");
 258         return adap->bus_recovery_info->recover_bus(adap);
 259 }
 260 EXPORT_SYMBOL_GPL(i2c_recover_bus);
 261
 262 static void i2c_init_recovery(struct i2c_adapter *adap)
 263 {
 264         struct i2c_bus_recovery_info *bri = adap->bus_recovery_info;
 265         char *err_str;
 266
 267         if (!bri)
 268                 return;
 269
 270         if (!bri->recover_bus) {
 271                 err_str = "no recover_bus() found";
 272                 goto err;
 273         }
 274
 275         /* Generic GPIO recovery */
 276         if (bri->recover_bus == i2c_generic_gpio_recovery) {
 277                 if (!gpio_is_valid(bri->scl_gpio)) {
 278                         err_str = "invalid SCL gpio";
 279                         goto err;
 280                 }
 281
 282                 if (gpio_is_valid(bri->sda_gpio))
 283                         bri->get_sda = get_sda_gpio_value;
 284                 else
 285                         bri->get_sda = NULL;
 286
 287                 bri->get_scl = get_scl_gpio_value;
 288                 bri->set_scl = set_scl_gpio_value;
 289         } else if (bri->recover_bus == i2c_generic_scl_recovery) {
 290                 /* Generic SCL recovery */
 291                 if (!bri->set_scl || !bri->get_scl) {
 292                         err_str = "no {get|set}_scl() found";
 293                         goto err;
 294                 }
 295         }
 296
 297         return;
 298  err:
 299         dev_err(&adap->dev, "Not using recovery: %s\n", err_str);
 300         adap->bus_recovery_info = NULL;
 301 }
 302
 303 static int i2c_smbus_host_notify_to_irq(const struct i2c_client *client)
 304 {
 305         struct i2c_adapter *adap = client->adapter;
 306         unsigned int irq;
 307
 308         if (!adap->host_notify_domain)
 309                 return -ENXIO;
 310
 311         if (client->flags & I2C_CLIENT_TEN)
 312                 return -EINVAL;
 313
 314         irq = irq_find_mapping(adap->host_notify_domain, client->addr);
 315         if (!irq)
 316                 irq = irq_create_mapping(adap->host_notify_domain,
 317                                          client->addr);
 318
 319         return irq > 0 ? irq : -ENXIO;
 320 }
 321
 322 static int i2c_device_probe(struct device *dev)
 323 {
 324         struct i2c_client       *client = i2c_verify_client(dev);
 325         struct i2c_driver       *driver;
 326         int status;
 327
 328         if (!client)
 329                 return 0;
 330
 331         driver = to_i2c_driver(dev->driver);
 332
 333         if (!client->irq && !driver->disable_i2c_core_irq_mapping) {
 334                 int irq = -ENOENT;
 335
 336                 if (client->flags & I2C_CLIENT_HOST_NOTIFY) {
 337                         dev_dbg(dev, "Using Host Notify IRQ\n");
 338                         irq = i2c_smbus_host_notify_to_irq(client);
 339                 } else if (dev->of_node) {
 340                         irq = of_irq_get_byname(dev->of_node, "irq");
 341                         if (irq == -EINVAL || irq == -ENODATA)
 342                                 irq = of_irq_get(dev->of_node, 0);
 343                 } else if (ACPI_COMPANION(dev)) {
 344                         irq = acpi_dev_gpio_irq_get(ACPI_COMPANION(dev), 0);
 345                 }
 346                 if (irq == -EPROBE_DEFER)
 347                         return irq;
 348
 349                 if (irq < 0)
 350                         irq = 0;
 351
 352                 client->irq = irq;
 353         }
 354
 355         /*
 356          * An I2C ID table is not mandatory, if and only if, a suitable Device
 357          * Tree match table entry is supplied for the probing device.
 358          */
 359         if (!driver->id_table &&
 360             !i2c_of_match_device(dev->driver->of_match_table, client))
 361                 return -ENODEV;
 362
 363         if (client->flags & I2C_CLIENT_WAKE) {
 364                 int wakeirq = -ENOENT;
 365
 366                 if (dev->of_node) {
 367                         wakeirq = of_irq_get_byname(dev->of_node, "wakeup");
 368                         if (wakeirq == -EPROBE_DEFER)
 369                                 return wakeirq;
 370                 }
 371
 372                 device_init_wakeup(&client->dev, true);
 373
 374                 if (wakeirq > 0 && wakeirq != client->irq)
 375                         status = dev_pm_set_dedicated_wake_irq(dev, wakeirq);
 376                 else if (client->irq > 0)
 377                         status = dev_pm_set_wake_irq(dev, client->irq);
 378                 else
 379                         status = 0;
 380
 381                 if (status)
 382                         dev_warn(&client->dev, "failed to set up wakeup irq\n");
 383         }
 384
 385         dev_dbg(dev, "probe\n");
 386
 387         status = of_clk_set_defaults(dev->of_node, false);
 388         if (status < 0)
 389                 goto err_clear_wakeup_irq;
 390
 391         status = dev_pm_domain_attach(&client->dev, true);
 392         if (status == -EPROBE_DEFER)
 393                 goto err_clear_wakeup_irq;
 394
 395         /*
 396          * When there are no more users of probe(),
 397          * rename probe_new to probe.
 398          */
 399         if (driver->probe_new)
 400                 status = driver->probe_new(client);
 401         else if (driver->probe)
 402                 status = driver->probe(client,
 403                                        i2c_match_id(driver->id_table, client));
 404         else
 405                 status = -EINVAL;
 406
 407         if (status)
 408                 goto err_detach_pm_domain;
 409
 410         return 0;
 411
 412 err_detach_pm_domain:
 413         dev_pm_domain_detach(&client->dev, true);
 414 err_clear_wakeup_irq:
 415         dev_pm_clear_wake_irq(&client->dev);
 416         device_init_wakeup(&client->dev, false);
 417         return status;
 418 }
 419
 420 static int i2c_device_remove(struct device *dev)
 421 {
 422         struct i2c_client       *client = i2c_verify_client(dev);
 423         struct i2c_driver       *driver;
 424         int status = 0;
 425
 426         if (!client || !dev->driver)
 427                 return 0;
 428
 429         driver = to_i2c_driver(dev->driver);
 430         if (driver->remove) {
 431                 dev_dbg(dev, "remove\n");
 432                 status = driver->remove(client);
 433         }
 434
 435         dev_pm_domain_detach(&client->dev, true);
 436
 437         dev_pm_clear_wake_irq(&client->dev);
 438         device_init_wakeup(&client->dev, false);
 439
 440         return status;
 441 }
 442
 443 static void i2c_device_shutdown(struct device *dev)
 444 {
 445         struct i2c_client *client = i2c_verify_client(dev);
 446         struct i2c_driver *driver;
 447
 448         if (!client || !dev->driver)
 449                 return;
 450         driver = to_i2c_driver(dev->driver);
 451         if (driver->shutdown)
 452                 driver->shutdown(client);
 453 }
 454
 455 static void i2c_client_dev_release(struct device *dev)
 456 {
 457         kfree(to_i2c_client(dev));
 458 }
 459
 460 static ssize_t
 461 show_name(struct device *dev, struct device_attribute *attr, char *buf)
 462 {
 463         return sprintf(buf, "%s\n", dev->type == &i2c_client_type ?
 464                        to_i2c_client(dev)->name : to_i2c_adapter(dev)->name);
 465 }
 466 static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 467
 468 static ssize_t
 469 show_modalias(struct device *dev, struct device_attribute *attr, char *buf)
 470 {
 471         struct i2c_client *client = to_i2c_client(dev);
 472         int len;
 473
 474         len = acpi_device_modalias(dev, buf, PAGE_SIZE -1);
 475         if (len != -ENODEV)
 476                 return len;
 477
 478         return sprintf(buf, "%s%s\n", I2C_MODULE_PREFIX, client->name);
 479 }
 480 static DEVICE_ATTR(modalias, S_IRUGO, show_modalias, NULL);
 481
 482 static struct attribute *i2c_dev_attrs[] = {
 483         &dev_attr_name.attr,
 484         /* modalias helps coldplug:  modprobe $(cat .../modalias) */
 485         &dev_attr_modalias.attr,
 486         NULL
 487 };
 488 ATTRIBUTE_GROUPS(i2c_dev);
 489
 490 struct bus_type i2c_bus_type = {
 491         .name           = "i2c",
 492         .match          = i2c_device_match,
 493         .probe          = i2c_device_probe,
 494         .remove         = i2c_device_remove,
 495         .shutdown       = i2c_device_shutdown,
 496 };
 497 EXPORT_SYMBOL_GPL(i2c_bus_type);
 498
 499 struct device_type i2c_client_type = {
 500         .groups         = i2c_dev_groups,
 501         .uevent         = i2c_device_uevent,
 502         .release        = i2c_client_dev_release,
 503 };
 504 EXPORT_SYMBOL_GPL(i2c_client_type);
 505
 506
 507 /**
 508  * i2c_verify_client - return parameter as i2c_client, or NULL
 509  * @dev: device, probably from some driver model iterator
 510  *
 511  * When traversing the driver model tree, perhaps using driver model
 512  * iterators like @device_for_each_child(), you can't assume very much
 513  * about the nodes you find.  Use this function to avoid oopses caused
 514  * by wrongly treating some non-I2C device as an i2c_client.
 515  */
 516 struct i2c_client *i2c_verify_client(struct device *dev)
 517 {
 518         return (dev->type == &i2c_client_type)
 519                         ? to_i2c_client(dev)
 520                         : NULL;
 521 }
 522 EXPORT_SYMBOL(i2c_verify_client);
 523
 524
 525 /* Return a unique address which takes the flags of the client into account */
 526 static unsigned short i2c_encode_flags_to_addr(struct i2c_client *client)
 527 {
 528         unsigned short addr = client->addr;
 529
 530         /* For some client flags, add an arbitrary offset to avoid collisions */
 531         if (client->flags & I2C_CLIENT_TEN)
 532                 addr |= I2C_ADDR_OFFSET_TEN_BIT;
 533
 534         if (client->flags & I2C_CLIENT_SLAVE)
 535                 addr |= I2C_ADDR_OFFSET_SLAVE;
 536
 537         return addr;
 538 }
 539
 540 /* This is a permissive address validity check, I2C address map constraints
 541  * are purposely not enforced, except for the general call address. */
 542 int i2c_check_addr_validity(unsigned addr, unsigned short flags)
 543 {
 544         if (flags & I2C_CLIENT_TEN) {
 545                 /* 10-bit address, all values are valid */
 546                 if (addr > 0x3ff)
 547                         return -EINVAL;
 548         } else {
 549                 /* 7-bit address, reject the general call address */
 550                 if (addr == 0x00 || addr > 0x7f)
 551                         return -EINVAL;
 552         }
 553         return 0;
 554 }
 555
 556 /* And this is a strict address validity check, used when probing. If a
 557  * device uses a reserved address, then it shouldn't be probed. 7-bit
 558  * addressing is assumed, 10-bit address devices are rare and should be
 559  * explicitly enumerated. */
 560 int i2c_check_7bit_addr_validity_strict(unsigned short addr)
 561 {
 562         /*
 563          * Reserved addresses per I2C specification:
 564          *  0x00       General call address / START byte
 565          *  0x01       CBUS address
 566          *  0x02       Reserved for different bus format
 567          *  0x03       Reserved for future purposes
 568          *  0x04-0x07  Hs-mode master code
 569          *  0x78-0x7b  10-bit slave addressing
 570          *  0x7c-0x7f  Reserved for future purposes
 571          */
 572         if (addr < 0x08 || addr > 0x77)
 573                 return -EINVAL;
 574         return 0;
 575 }
 576
 577 static int __i2c_check_addr_busy(struct device *dev, void *addrp)
 578 {
 579         struct i2c_client       *client = i2c_verify_client(dev);
 580         int                     addr = *(int *)addrp;
 581
 582         if (client && i2c_encode_flags_to_addr(client) == addr)
 583                 return -EBUSY;
 584         return 0;
 585 }
 586
 587 /* walk up mux tree */
 588 static int i2c_check_mux_parents(struct i2c_adapter *adapter, int addr)
 589 {
 590         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 591         int result;
 592
 593         result = device_for_each_child(&adapter->dev, &addr,
 594                                         __i2c_check_addr_busy);
 595
 596         if (!result && parent)
 597                 result = i2c_check_mux_parents(parent, addr);
 598
 599         return result;
 600 }
 601
 602 /* recurse down mux tree */
 603 static int i2c_check_mux_children(struct device *dev, void *addrp)
 604 {
 605         int result;
 606
 607         if (dev->type == &i2c_adapter_type)
 608                 result = device_for_each_child(dev, addrp,
 609                                                 i2c_check_mux_children);
 610         else
 611                 result = __i2c_check_addr_busy(dev, addrp);
 612
 613         return result;
 614 }
 615
 616 static int i2c_check_addr_busy(struct i2c_adapter *adapter, int addr)
 617 {
 618         struct i2c_adapter *parent = i2c_parent_is_i2c_adapter(adapter);
 619         int result = 0;
 620
 621         if (parent)
 622                 result = i2c_check_mux_parents(parent, addr);
 623
 624         if (!result)
 625                 result = device_for_each_child(&adapter->dev, &addr,
 626                                                 i2c_check_mux_children);
 627
 628         return result;
 629 }
 630
 631 /**
 632  * i2c_adapter_lock_bus - Get exclusive access to an I2C bus segment
 633  * @adapter: Target I2C bus segment
 634  * @flags: I2C_LOCK_ROOT_ADAPTER locks the root i2c adapter, I2C_LOCK_SEGMENT
 635  *      locks only this branch in the adapter tree
 636  */
 637 static void i2c_adapter_lock_bus(struct i2c_adapter *adapter,
 638                                  unsigned int flags)
 639 {
 640         rt_mutex_lock(&adapter->bus_lock);
 641 }
 642
 643 /**
 644  * i2c_adapter_trylock_bus - Try to get exclusive access to an I2C bus segment
 645  * @adapter: Target I2C bus segment
 646  * @flags: I2C_LOCK_ROOT_ADAPTER trylocks the root i2c adapter, I2C_LOCK_SEGMENT
 647  *      trylocks only this branch in the adapter tree
 648  */
 649 static int i2c_adapter_trylock_bus(struct i2c_adapter *adapter,
 650                                    unsigned int flags)
 651 {
 652         return rt_mutex_trylock(&adapter->bus_lock);
 653 }
 654
 655 /**
 656  * i2c_adapter_unlock_bus - Release exclusive access to an I2C bus segment
 657  * @adapter: Target I2C bus segment
 658  * @flags: I2C_LOCK_ROOT_ADAPTER unlocks the root i2c adapter, I2C_LOCK_SEGMENT
 659  *      unlocks only this branch in the adapter tree
 660  */
 661 static void i2c_adapter_unlock_bus(struct i2c_adapter *adapter,
 662                                    unsigned int flags)
 663 {
 664         rt_mutex_unlock(&adapter->bus_lock);
 665 }
 666
 667 static void i2c_dev_set_name(struct i2c_adapter *adap,
 668                              struct i2c_client *client)
 669 {
 670         struct acpi_device *adev = ACPI_COMPANION(&client->dev);
 671
 672         if (adev) {
 673                 dev_set_name(&client->dev, "i2c-%s", acpi_dev_name(adev));
 674                 return;
 675         }
 676
 677         dev_set_name(&client->dev, "%d-%04x", i2c_adapter_id(adap),
 678                      i2c_encode_flags_to_addr(client));
 679 }
 680
 681 static int i2c_dev_irq_from_resources(const struct resource *resources,
 682                                       unsigned int num_resources)
 683 {
 684         struct irq_data *irqd;
 685         int i;
 686
 687         for (i = 0; i < num_resources; i++) {
 688                 const struct resource *r = &resources[i];
 689
 690                 if (resource_type(r) != IORESOURCE_IRQ)
 691                         continue;
 692
 693                 if (r->flags & IORESOURCE_BITS) {
 694                         irqd = irq_get_irq_data(r->start);
 695                         if (!irqd)
 696                                 break;
 697
 698                         irqd_set_trigger_type(irqd, r->flags & IORESOURCE_BITS);
 699                 }
 700
 701                 return r->start;
 702         }
 703
 704         return 0;
 705 }
 706
 707 /**
 708  * i2c_new_device - instantiate an i2c device
 709  * @adap: the adapter managing the device
 710  * @info: describes one I2C device; bus_num is ignored
 711  * Context: can sleep
 712  *
 713  * Create an i2c device. Binding is handled through driver model
 714  * probe()/remove() methods.  A driver may be bound to this device when we
 715  * return from this function, or any later moment (e.g. maybe hotplugging will
 716  * load the driver module).  This call is not appropriate for use by mainboard
 717  * initialization logic, which usually runs during an arch_initcall() long
 718  * before any i2c_adapter could exist.
 719  *
 720  * This returns the new i2c client, which may be saved for later use with
 721  * i2c_unregister_device(); or NULL to indicate an error.
 722  */
 723 struct i2c_client *
 724 i2c_new_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 725 {
 726         struct i2c_client       *client;
 727         int                     status;
 728
 729         client = kzalloc(sizeof *client, GFP_KERNEL);
 730         if (!client)
 731                 return NULL;
 732
 733         client->adapter = adap;
 734
 735         client->dev.platform_data = info->platform_data;
 736
 737         if (info->archdata)
 738                 client->dev.archdata = *info->archdata;
 739
 740         client->flags = info->flags;
 741         client->addr = info->addr;
 742
 743         client->irq = info->irq;
 744         if (!client->irq)
 745                 client->irq = i2c_dev_irq_from_resources(info->resources,
 746                                                          info->num_resources);
 747
 748         strlcpy(client->name, info->type, sizeof(client->name));
 749
 750         status = i2c_check_addr_validity(client->addr, client->flags);
 751         if (status) {
 752                 dev_err(&adap->dev, "Invalid %d-bit I2C address 0x%02hx\n",
 753                         client->flags & I2C_CLIENT_TEN ? 10 : 7, client->addr);
 754                 goto out_err_silent;
 755         }
 756
 757         /* Check for address business */
 758         status = i2c_check_addr_busy(adap, i2c_encode_flags_to_addr(client));
 759         if (status)
 760                 goto out_err;
 761
 762         client->dev.parent = &client->adapter->dev;
 763         client->dev.bus = &i2c_bus_type;
 764         client->dev.type = &i2c_client_type;
 765         client->dev.of_node = info->of_node;
 766         client->dev.fwnode = info->fwnode;
 767
 768         i2c_dev_set_name(adap, client);
 769
 770         if (info->properties) {
 771                 status = device_add_properties(&client->dev, info->properties);
 772                 if (status) {
 773                         dev_err(&adap->dev,
 774                                 "Failed to add properties to client %s: %d\n",
 775                                 client->name, status);
 776                         goto out_err;
 777                 }
 778         }
 779
 780         status = device_register(&client->dev);
 781         if (status)
 782                 goto out_free_props;
 783
 784         dev_dbg(&adap->dev, "client [%s] registered with bus id %s\n",
 785                 client->name, dev_name(&client->dev));
 786
 787         return client;
 788
 789 out_free_props:
 790         if (info->properties)
 791                 device_remove_properties(&client->dev);
 792 out_err:
 793         dev_err(&adap->dev,
 794                 "Failed to register i2c client %s at 0x%02x (%d)\n",
 795                 client->name, client->addr, status);
 796 out_err_silent:
 797         kfree(client);
 798         return NULL;
 799 }
 800 EXPORT_SYMBOL_GPL(i2c_new_device);
 801
 802
 803 /**
 804  * i2c_unregister_device - reverse effect of i2c_new_device()
 805  * @client: value returned from i2c_new_device()
 806  * Context: can sleep
 807  */
 808 void i2c_unregister_device(struct i2c_client *client)
 809 {
 810         if (client->dev.of_node)
 811                 of_node_clear_flag(client->dev.of_node, OF_POPULATED);
 812         if (ACPI_COMPANION(&client->dev))
 813                 acpi_device_clear_enumerated(ACPI_COMPANION(&client->dev));
 814         device_unregister(&client->dev);
 815 }
 816 EXPORT_SYMBOL_GPL(i2c_unregister_device);
 817
 818
 819 static const struct i2c_device_id dummy_id[] = {
 820         { "dummy", 0 },
 821         { },
 822 };
 823
 824 static int dummy_probe(struct i2c_client *client,
 825                        const struct i2c_device_id *id)
 826 {
 827         return 0;
 828 }
 829
 830 static int dummy_remove(struct i2c_client *client)
 831 {
 832         return 0;
 833 }
 834
 835 static struct i2c_driver dummy_driver = {
 836         .driver.name    = "dummy",
 837         .probe          = dummy_probe,
 838         .remove         = dummy_remove,
 839         .id_table       = dummy_id,
 840 };
 841
 842 /**
 843  * i2c_new_dummy - return a new i2c device bound to a dummy driver
 844  * @adapter: the adapter managing the device
 845  * @address: seven bit address to be used
 846  * Context: can sleep
 847  *
 848  * This returns an I2C client bound to the "dummy" driver, intended for use
 849  * with devices that consume multiple addresses.  Examples of such chips
 850  * include various EEPROMS (like 24c04 and 24c08 models).
 851  *
 852  * These dummy devices have two main uses.  First, most I2C and SMBus calls
 853  * except i2c_transfer() need a client handle; the dummy will be that handle.
 854  * And second, this prevents the specified address from being bound to a
 855  * different driver.
 856  *
 857  * This returns the new i2c client, which should be saved for later use with
 858  * i2c_unregister_device(); or NULL to indicate an error.
 859  */
 860 struct i2c_client *i2c_new_dummy(struct i2c_adapter *adapter, u16 address)
 861 {
 862         struct i2c_board_info info = {
 863                 I2C_BOARD_INFO("dummy", address),
 864         };
 865
 866         return i2c_new_device(adapter, &info);
 867 }
 868 EXPORT_SYMBOL_GPL(i2c_new_dummy);
 869
 870 /**
 871  * i2c_new_secondary_device - Helper to get the instantiated secondary address
 872  * and create the associated device
 873  * @client: Handle to the primary client
 874  * @name: Handle to specify which secondary address to get
 875  * @default_addr: Used as a fallback if no secondary address was specified
 876  * Context: can sleep
 877  *
 878  * I2C clients can be composed of multiple I2C slaves bound together in a single
 879  * component. The I2C client driver then binds to the master I2C slave and needs
 880  * to create I2C dummy clients to communicate with all the other slaves.
 881  *
 882  * This function creates and returns an I2C dummy client whose I2C address is
 883  * retrieved from the platform firmware based on the given slave name. If no
 884  * address is specified by the firmware default_addr is used.
 885  *
 886  * On DT-based platforms the address is retrieved from the "reg" property entry
 887  * cell whose "reg-names" value matches the slave name.
 888  *
 889  * This returns the new i2c client, which should be saved for later use with
 890  * i2c_unregister_device(); or NULL to indicate an error.
 891  */
 892 struct i2c_client *i2c_new_secondary_device(struct i2c_client *client,
 893                                                 const char *name,
 894                                                 u16 default_addr)
 895 {
 896         struct device_node *np = client->dev.of_node;
 897         u32 addr = default_addr;
 898         int i;
 899
 900         if (np) {
 901                 i = of_property_match_string(np, "reg-names", name);
 902                 if (i >= 0)
 903                         of_property_read_u32_index(np, "reg", i, &addr);
 904         }
 905
 906         dev_dbg(&client->adapter->dev, "Address for %s : 0x%x\n", name, addr);
 907         return i2c_new_dummy(client->adapter, addr);
 908 }
 909 EXPORT_SYMBOL_GPL(i2c_new_secondary_device);
 910
 911 /* ------------------------------------------------------------------------- */
 912
 913 /* I2C bus adapters -- one roots each I2C or SMBUS segment */
 914
 915 static void i2c_adapter_dev_release(struct device *dev)
 916 {
 917         struct i2c_adapter *adap = to_i2c_adapter(dev);
 918         complete(&adap->dev_released);
 919 }
 920
 921 unsigned int i2c_adapter_depth(struct i2c_adapter *adapter)
 922 {
 923         unsigned int depth = 0;
 924
 925         while ((adapter = i2c_parent_is_i2c_adapter(adapter)))
 926                 depth++;
 927
 928         WARN_ONCE(depth >= MAX_LOCKDEP_SUBCLASSES,
 929                   "adapter depth exceeds lockdep subclass limit\n");
 930
 931         return depth;
 932 }
 933 EXPORT_SYMBOL_GPL(i2c_adapter_depth);
 934
 935 /*
 936  * Let users instantiate I2C devices through sysfs. This can be used when
 937  * platform initialization code doesn't contain the proper data for
 938  * whatever reason. Also useful for drivers that do device detection and
 939  * detection fails, either because the device uses an unexpected address,
 940  * or this is a compatible device with different ID register values.
 941  *
 942  * Parameter checking may look overzealous, but we really don't want
 943  * the user to provide incorrect parameters.
 944  */
 945 static ssize_t
 946 i2c_sysfs_new_device(struct device *dev, struct device_attribute *attr,
 947                      const char *buf, size_t count)
 948 {
 949         struct i2c_adapter *adap = to_i2c_adapter(dev);
 950         struct i2c_board_info info;
 951         struct i2c_client *client;
 952         char *blank, end;
 953         int res;
 954
 955         memset(&info, 0, sizeof(struct i2c_board_info));
 956
 957         blank = strchr(buf, ' ');
 958         if (!blank) {
 959                 dev_err(dev, "%s: Missing parameters\n", "new_device");
 960                 return -EINVAL;
 961         }
 962         if (blank - buf > I2C_NAME_SIZE - 1) {
 963                 dev_err(dev, "%s: Invalid device name\n", "new_device");
 964                 return -EINVAL;
 965         }
 966         memcpy(info.type, buf, blank - buf);
 967
 968         /* Parse remaining parameters, reject extra parameters */
 969         res = sscanf(++blank, "%hi%c", &info.addr, &end);
 970         if (res < 1) {
 971                 dev_err(dev, "%s: Can't parse I2C address\n", "new_device");
 972                 return -EINVAL;
 973         }
 974         if (res > 1  && end != '\n') {
 975                 dev_err(dev, "%s: Extra parameters\n", "new_device");
 976                 return -EINVAL;
 977         }
 978
 979         if ((info.addr & I2C_ADDR_OFFSET_TEN_BIT) == I2C_ADDR_OFFSET_TEN_BIT) {
 980                 info.addr &= ~I2C_ADDR_OFFSET_TEN_BIT;
 981                 info.flags |= I2C_CLIENT_TEN;
 982         }
 983
 984         if (info.addr & I2C_ADDR_OFFSET_SLAVE) {
 985                 info.addr &= ~I2C_ADDR_OFFSET_SLAVE;
 986                 info.flags |= I2C_CLIENT_SLAVE;
 987         }
 988
 989         client = i2c_new_device(adap, &info);
 990         if (!client)
 991                 return -EINVAL;
 992
 993         /* Keep track of the added device */
 994         mutex_lock(&adap->userspace_clients_lock);
 995         list_add_tail(&client->detected, &adap->userspace_clients);
 996         mutex_unlock(&adap->userspace_clients_lock);
 997         dev_info(dev, "%s: Instantiated device %s at 0x%02hx\n", "new_device",
 998                  info.type, info.addr);
 999
1000         return count;
1001 }
1002 static DEVICE_ATTR(new_device, S_IWUSR, NULL, i2c_sysfs_new_device);
1003
1004 /*
1005  * And of course let the users delete the devices they instantiated, if
1006  * they got it wrong. This interface can only be used to delete devices
1007  * instantiated by i2c_sysfs_new_device above. This guarantees that we
1008  * don't delete devices to which some kernel code still has references.
1009  *
1010  * Parameter checking may look overzealous, but we really don't want
1011  * the user to delete the wrong device.
1012  */
1013 static ssize_t
1014 i2c_sysfs_delete_device(struct device *dev, struct device_attribute *attr,
1015                         const char *buf, size_t count)
1016 {
1017         struct i2c_adapter *adap = to_i2c_adapter(dev);
1018         struct i2c_client *client, *next;
1019         unsigned short addr;
1020         char end;
1021         int res;
1022
1023         /* Parse parameters, reject extra parameters */
1024         res = sscanf(buf, "%hi%c", &addr, &end);
1025         if (res < 1) {
1026                 dev_err(dev, "%s: Can't parse I2C address\n", "delete_device");
1027                 return -EINVAL;
1028         }
1029         if (res > 1  && end != '\n') {
1030                 dev_err(dev, "%s: Extra parameters\n", "delete_device");
1031                 return -EINVAL;
1032         }
1033
1034         /* Make sure the device was added through sysfs */
1035         res = -ENOENT;
1036         mutex_lock_nested(&adap->userspace_clients_lock,
1037                           i2c_adapter_depth(adap));
1038         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1039                                  detected) {
1040                 if (i2c_encode_flags_to_addr(client) == addr) {
1041                         dev_info(dev, "%s: Deleting device %s at 0x%02hx\n",
1042                                  "delete_device", client->name, client->addr);
1043
1044                         list_del(&client->detected);
1045                         i2c_unregister_device(client);
1046                         res = count;
1047                         break;
1048                 }
1049         }
1050         mutex_unlock(&adap->userspace_clients_lock);
1051
1052         if (res < 0)
1053                 dev_err(dev, "%s: Can't find device in list\n",
1054                         "delete_device");
1055         return res;
1056 }
1057 static DEVICE_ATTR_IGNORE_LOCKDEP(delete_device, S_IWUSR, NULL,
1058                                    i2c_sysfs_delete_device);
1059
1060 static struct attribute *i2c_adapter_attrs[] = {
1061         &dev_attr_name.attr,
1062         &dev_attr_new_device.attr,
1063         &dev_attr_delete_device.attr,
1064         NULL
1065 };
1066 ATTRIBUTE_GROUPS(i2c_adapter);
1067
1068 struct device_type i2c_adapter_type = {
1069         .groups         = i2c_adapter_groups,
1070         .release        = i2c_adapter_dev_release,
1071 };
1072 EXPORT_SYMBOL_GPL(i2c_adapter_type);
1073
1074 /**
1075  * i2c_verify_adapter - return parameter as i2c_adapter or NULL
1076  * @dev: device, probably from some driver model iterator
1077  *
1078  * When traversing the driver model tree, perhaps using driver model
1079  * iterators like @device_for_each_child(), you can't assume very much
1080  * about the nodes you find.  Use this function to avoid oopses caused
1081  * by wrongly treating some non-I2C device as an i2c_adapter.
1082  */
1083 struct i2c_adapter *i2c_verify_adapter(struct device *dev)
1084 {
1085         return (dev->type == &i2c_adapter_type)
1086                         ? to_i2c_adapter(dev)
1087                         : NULL;
1088 }
1089 EXPORT_SYMBOL(i2c_verify_adapter);
1090
1091 #ifdef CONFIG_I2C_COMPAT
1092 static struct class_compat *i2c_adapter_compat_class;
1093 #endif
1094
1095 static void i2c_scan_static_board_info(struct i2c_adapter *adapter)
1096 {
1097         struct i2c_devinfo      *devinfo;
1098
1099         down_read(&__i2c_board_lock);
1100         list_for_each_entry(devinfo, &__i2c_board_list, list) {
1101                 if (devinfo->busnum == adapter->nr
1102                                 && !i2c_new_device(adapter,
1103                                                 &devinfo->board_info))
1104                         dev_err(&adapter->dev,
1105                                 "Can't create device at 0x%02x\n",
1106                                 devinfo->board_info.addr);
1107         }
1108         up_read(&__i2c_board_lock);
1109 }
1110
1111 static int i2c_do_add_adapter(struct i2c_driver *driver,
1112                               struct i2c_adapter *adap)
1113 {
1114         /* Detect supported devices on that bus, and instantiate them */
1115         i2c_detect(adap, driver);
1116
1117         /* Let legacy drivers scan this bus for matching devices */
1118         if (driver->attach_adapter) {
1119                 dev_warn(&adap->dev, "%s: attach_adapter method is deprecated\n",
1120                          driver->driver.name);
1121                 dev_warn(&adap->dev,
1122                          "Please use another way to instantiate your i2c_client\n");
1123                 /* We ignore the return code; if it fails, too bad */
1124                 driver->attach_adapter(adap);
1125         }
1126         return 0;
1127 }
1128
1129 static int __process_new_adapter(struct device_driver *d, void *data)
1130 {
1131         return i2c_do_add_adapter(to_i2c_driver(d), data);
1132 }
1133
1134 static const struct i2c_lock_operations i2c_adapter_lock_ops = {
1135         .lock_bus =    i2c_adapter_lock_bus,
1136         .trylock_bus = i2c_adapter_trylock_bus,
1137         .unlock_bus =  i2c_adapter_unlock_bus,
1138 };
1139
1140 static void i2c_host_notify_irq_teardown(struct i2c_adapter *adap)
1141 {
1142         struct irq_domain *domain = adap->host_notify_domain;
1143         irq_hw_number_t hwirq;
1144
1145         if (!domain)
1146                 return;
1147
1148         for (hwirq = 0 ; hwirq < I2C_ADDR_7BITS_COUNT ; hwirq++)
1149                 irq_dispose_mapping(irq_find_mapping(domain, hwirq));
1150
1151         irq_domain_remove(domain);
1152         adap->host_notify_domain = NULL;
1153 }
1154
1155 static int i2c_host_notify_irq_map(struct irq_domain *h,
1156                                           unsigned int virq,
1157                                           irq_hw_number_t hw_irq_num)
1158 {
1159         irq_set_chip_and_handler(virq, &dummy_irq_chip, handle_simple_irq);
1160
1161         return 0;
1162 }
1163
1164 static const struct irq_domain_ops i2c_host_notify_irq_ops = {
1165         .map = i2c_host_notify_irq_map,
1166 };
1167
1168 static int i2c_setup_host_notify_irq_domain(struct i2c_adapter *adap)
1169 {
1170         struct irq_domain *domain;
1171
1172         if (!i2c_check_functionality(adap, I2C_FUNC_SMBUS_HOST_NOTIFY))
1173                 return 0;
1174
1175         domain = irq_domain_create_linear(adap->dev.fwnode,
1176                                           I2C_ADDR_7BITS_COUNT,
1177                                           &i2c_host_notify_irq_ops, adap);
1178         if (!domain)
1179                 return -ENOMEM;
1180
1181         adap->host_notify_domain = domain;
1182
1183         return 0;
1184 }
1185
1186 /**
1187  * i2c_handle_smbus_host_notify - Forward a Host Notify event to the correct
1188  * I2C client.
1189  * @adap: the adapter
1190  * @addr: the I2C address of the notifying device
1191  * Context: can't sleep
1192  *
1193  * Helper function to be called from an I2C bus driver's interrupt
1194  * handler. It will schedule the Host Notify IRQ.
1195  */
1196 int i2c_handle_smbus_host_notify(struct i2c_adapter *adap, unsigned short addr)
1197 {
1198         int irq;
1199
1200         if (!adap)
1201                 return -EINVAL;
1202
1203         irq = irq_find_mapping(adap->host_notify_domain, addr);
1204         if (irq <= 0)
1205                 return -ENXIO;
1206
1207         generic_handle_irq(irq);
1208
1209         return 0;
1210 }
1211 EXPORT_SYMBOL_GPL(i2c_handle_smbus_host_notify);
1212
1213 static int i2c_register_adapter(struct i2c_adapter *adap)
1214 {
1215         int res = -EINVAL;
1216
1217         /* Can't register until after driver model init */
1218         if (WARN_ON(!is_registered)) {
1219                 res = -EAGAIN;
1220                 goto out_list;
1221         }
1222
1223         /* Sanity checks */
1224         if (WARN(!adap->name[0], "i2c adapter has no name"))
1225                 goto out_list;
1226
1227         if (!adap->algo) {
1228                 pr_err("adapter '%s': no algo supplied!\n", adap->name);
1229                 goto out_list;
1230         }
1231
1232         if (!adap->lock_ops)
1233                 adap->lock_ops = &i2c_adapter_lock_ops;
1234
1235         rt_mutex_init(&adap->bus_lock);
1236         rt_mutex_init(&adap->mux_lock);
1237         mutex_init(&adap->userspace_clients_lock);
1238         INIT_LIST_HEAD(&adap->userspace_clients);
1239
1240         /* Set default timeout to 1 second if not already set */
1241         if (adap->timeout == 0)
1242                 adap->timeout = HZ;
1243
1244         /* register soft irqs for Host Notify */
1245         res = i2c_setup_host_notify_irq_domain(adap);
1246         if (res) {
1247                 pr_err("adapter '%s': can't create Host Notify IRQs (%d)\n",
1248                        adap->name, res);
1249                 goto out_list;
1250         }
1251
1252         dev_set_name(&adap->dev, "i2c-%d", adap->nr);
1253         adap->dev.bus = &i2c_bus_type;
1254         adap->dev.type = &i2c_adapter_type;
1255         res = device_register(&adap->dev);
1256         if (res) {
1257                 pr_err("adapter '%s': can't register device (%d)\n", adap->name, res);
1258                 goto out_list;
1259         }
1260
1261         dev_dbg(&adap->dev, "adapter [%s] registered\n", adap->name);
1262
1263         pm_runtime_no_callbacks(&adap->dev);
1264         pm_suspend_ignore_children(&adap->dev, true);
1265         pm_runtime_enable(&adap->dev);
1266
1267 #ifdef CONFIG_I2C_COMPAT
1268         res = class_compat_create_link(i2c_adapter_compat_class, &adap->dev,
1269                                        adap->dev.parent);
1270         if (res)
1271                 dev_warn(&adap->dev,
1272                          "Failed to create compatibility class link\n");
1273 #endif
1274
1275         i2c_init_recovery(adap);
1276
1277         /* create pre-declared device nodes */
1278         of_i2c_register_devices(adap);
1279         i2c_acpi_register_devices(adap);
1280         i2c_acpi_install_space_handler(adap);
1281
1282         if (adap->nr < __i2c_first_dynamic_bus_num)
1283                 i2c_scan_static_board_info(adap);
1284
1285         /* Notify drivers */
1286         mutex_lock(&core_lock);
1287         bus_for_each_drv(&i2c_bus_type, NULL, adap, __process_new_adapter);
1288         mutex_unlock(&core_lock);
1289
1290         return 0;
1291
1292 out_list:
1293         mutex_lock(&core_lock);
1294         idr_remove(&i2c_adapter_idr, adap->nr);
1295         mutex_unlock(&core_lock);
1296         return res;
1297 }
1298
1299 /**
1300  * __i2c_add_numbered_adapter - i2c_add_numbered_adapter where nr is never -1
1301  * @adap: the adapter to register (with adap->nr initialized)
1302  * Context: can sleep
1303  *
1304  * See i2c_add_numbered_adapter() for details.
1305  */
1306 static int __i2c_add_numbered_adapter(struct i2c_adapter *adap)
1307 {
1308         int id;
1309
1310         mutex_lock(&core_lock);
1311         id = idr_alloc(&i2c_adapter_idr, adap, adap->nr, adap->nr + 1, GFP_KERNEL);
1312         mutex_unlock(&core_lock);
1313         if (WARN(id < 0, "couldn't get idr"))
1314                 return id == -ENOSPC ? -EBUSY : id;
1315
1316         return i2c_register_adapter(adap);
1317 }
1318
1319 /**
1320  * i2c_add_adapter - declare i2c adapter, use dynamic bus number
1321  * @adapter: the adapter to add
1322  * Context: can sleep
1323  *
1324  * This routine is used to declare an I2C adapter when its bus number
1325  * doesn't matter or when its bus number is specified by an dt alias.
1326  * Examples of bases when the bus number doesn't matter: I2C adapters
1327  * dynamically added by USB links or PCI plugin cards.
1328  *
1329  * When this returns zero, a new bus number was allocated and stored
1330  * in adap->nr, and the specified adapter became available for clients.
1331  * Otherwise, a negative errno value is returned.
1332  */
1333 int i2c_add_adapter(struct i2c_adapter *adapter)
1334 {
1335         struct device *dev = &adapter->dev;
1336         int id;
1337
1338         if (dev->of_node) {
1339                 id = of_alias_get_id(dev->of_node, "i2c");
1340                 if (id >= 0) {
1341                         adapter->nr = id;
1342                         return __i2c_add_numbered_adapter(adapter);
1343                 }
1344         }
1345
1346         mutex_lock(&core_lock);
1347         id = idr_alloc(&i2c_adapter_idr, adapter,
1348                        __i2c_first_dynamic_bus_num, 0, GFP_KERNEL);
1349         mutex_unlock(&core_lock);
1350         if (WARN(id < 0, "couldn't get idr"))
1351                 return id;
1352
1353         adapter->nr = id;
1354
1355         return i2c_register_adapter(adapter);
1356 }
1357 EXPORT_SYMBOL(i2c_add_adapter);
1358
1359 /**
1360  * i2c_add_numbered_adapter - declare i2c adapter, use static bus number
1361  * @adap: the adapter to register (with adap->nr initialized)
1362  * Context: can sleep
1363  *
1364  * This routine is used to declare an I2C adapter when its bus number
1365  * matters.  For example, use it for I2C adapters from system-on-chip CPUs,
1366  * or otherwise built in to the system's mainboard, and where i2c_board_info
1367  * is used to properly configure I2C devices.
1368  *
1369  * If the requested bus number is set to -1, then this function will behave
1370  * identically to i2c_add_adapter, and will dynamically assign a bus number.
1371  *
1372  * If no devices have pre-been declared for this bus, then be sure to
1373  * register the adapter before any dynamically allocated ones.  Otherwise
1374  * the required bus ID may not be available.
1375  *
1376  * When this returns zero, the specified adapter became available for
1377  * clients using the bus number provided in adap->nr.  Also, the table
1378  * of I2C devices pre-declared using i2c_register_board_info() is scanned,
1379  * and the appropriate driver model device nodes are created.  Otherwise, a
1380  * negative errno value is returned.
1381  */
1382 int i2c_add_numbered_adapter(struct i2c_adapter *adap)
1383 {
1384         if (adap->nr == -1) /* -1 means dynamically assign bus id */
1385                 return i2c_add_adapter(adap);
1386
1387         return __i2c_add_numbered_adapter(adap);
1388 }
1389 EXPORT_SYMBOL_GPL(i2c_add_numbered_adapter);
1390
1391 static void i2c_do_del_adapter(struct i2c_driver *driver,
1392                               struct i2c_adapter *adapter)
1393 {
1394         struct i2c_client *client, *_n;
1395
1396         /* Remove the devices we created ourselves as the result of hardware
1397          * probing (using a driver's detect method) */
1398         list_for_each_entry_safe(client, _n, &driver->clients, detected) {
1399                 if (client->adapter == adapter) {
1400                         dev_dbg(&adapter->dev, "Removing %s at 0x%x\n",
1401                                 client->name, client->addr);
1402                         list_del(&client->detected);
1403                         i2c_unregister_device(client);
1404                 }
1405         }
1406 }
1407
1408 static int __unregister_client(struct device *dev, void *dummy)
1409 {
1410         struct i2c_client *client = i2c_verify_client(dev);
1411         if (client && strcmp(client->name, "dummy"))
1412                 i2c_unregister_device(client);
1413         return 0;
1414 }
1415
1416 static int __unregister_dummy(struct device *dev, void *dummy)
1417 {
1418         struct i2c_client *client = i2c_verify_client(dev);
1419         if (client)
1420                 i2c_unregister_device(client);
1421         return 0;
1422 }
1423
1424 static int __process_removed_adapter(struct device_driver *d, void *data)
1425 {
1426         i2c_do_del_adapter(to_i2c_driver(d), data);
1427         return 0;
1428 }
1429
1430 /**
1431  * i2c_del_adapter - unregister I2C adapter
1432  * @adap: the adapter being unregistered
1433  * Context: can sleep
1434  *
1435  * This unregisters an I2C adapter which was previously registered
1436  * by @i2c_add_adapter or @i2c_add_numbered_adapter.
1437  */
1438 void i2c_del_adapter(struct i2c_adapter *adap)
1439 {
1440         struct i2c_adapter *found;
1441         struct i2c_client *client, *next;
1442
1443         /* First make sure that this adapter was ever added */
1444         mutex_lock(&core_lock);
1445         found = idr_find(&i2c_adapter_idr, adap->nr);
1446         mutex_unlock(&core_lock);
1447         if (found != adap) {
1448                 pr_debug("attempting to delete unregistered adapter [%s]\n", adap->name);
1449                 return;
1450         }
1451
1452         i2c_acpi_remove_space_handler(adap);
1453         /* Tell drivers about this removal */
1454         mutex_lock(&core_lock);
1455         bus_for_each_drv(&i2c_bus_type, NULL, adap,
1456                                __process_removed_adapter);
1457         mutex_unlock(&core_lock);
1458
1459         /* Remove devices instantiated from sysfs */
1460         mutex_lock_nested(&adap->userspace_clients_lock,
1461                           i2c_adapter_depth(adap));
1462         list_for_each_entry_safe(client, next, &adap->userspace_clients,
1463                                  detected) {
1464                 dev_dbg(&adap->dev, "Removing %s at 0x%x\n", client->name,
1465                         client->addr);
1466                 list_del(&client->detected);
1467                 i2c_unregister_device(client);
1468         }
1469         mutex_unlock(&adap->userspace_clients_lock);
1470
1471         /* Detach any active clients. This can't fail, thus we do not
1472          * check the returned value. This is a two-pass process, because
1473          * we can't remove the dummy devices during the first pass: they
1474          * could have been instantiated by real devices wishing to clean
1475          * them up properly, so we give them a chance to do that first. */
1476         device_for_each_child(&adap->dev, NULL, __unregister_client);
1477         device_for_each_child(&adap->dev, NULL, __unregister_dummy);
1478
1479 #ifdef CONFIG_I2C_COMPAT
1480         class_compat_remove_link(i2c_adapter_compat_class, &adap->dev,
1481                                  adap->dev.parent);
1482 #endif
1483
1484         /* device name is gone after device_unregister */
1485         dev_dbg(&adap->dev, "adapter [%s] unregistered\n", adap->name);
1486
1487         pm_runtime_disable(&adap->dev);
1488
1489         i2c_host_notify_irq_teardown(adap);
1490
1491         /* wait until all references to the device are gone
1492          *
1493          * FIXME: This is old code and should ideally be replaced by an
1494          * alternative which results in decoupling the lifetime of the struct
1495          * device from the i2c_adapter, like spi or netdev do. Any solution
1496          * should be thoroughly tested with DEBUG_KOBJECT_RELEASE enabled!
1497          */
1498         init_completion(&adap->dev_released);
1499         device_unregister(&adap->dev);
1500         wait_for_completion(&adap->dev_released);
1501
1502         /* free bus id */
1503         mutex_lock(&core_lock);
1504         idr_remove(&i2c_adapter_idr, adap->nr);
1505         mutex_unlock(&core_lock);
1506
1507         /* Clear the device structure in case this adapter is ever going to be
1508            added again */
1509         memset(&adap->dev, 0, sizeof(adap->dev));
1510 }
1511 EXPORT_SYMBOL(i2c_del_adapter);
1512
1513 /**
1514  * i2c_parse_fw_timings - get I2C related timing parameters from firmware
1515  * @dev: The device to scan for I2C timing properties
1516  * @t: the i2c_timings struct to be filled with values
1517  * @use_defaults: bool to use sane defaults derived from the I2C specification
1518  *                when properties are not found, otherwise use 0
1519  *
1520  * Scan the device for the generic I2C properties describing timing parameters
1521  * for the signal and fill the given struct with the results. If a property was
1522  * not found and use_defaults was true, then maximum timings are assumed which
1523  * are derived from the I2C specification. If use_defaults is not used, the
1524  * results will be 0, so drivers can apply their own defaults later. The latter
1525  * is mainly intended for avoiding regressions of existing drivers which want
1526  * to switch to this function. New drivers almost always should use the defaults.
1527  */
1528
1529 void i2c_parse_fw_timings(struct device *dev, struct i2c_timings *t, bool use_defaults)
1530 {
1531         int ret;
1532
1533         memset(t, 0, sizeof(*t));
1534
1535         ret = device_property_read_u32(dev, "clock-frequency", &t->bus_freq_hz);
1536         if (ret && use_defaults)
1537                 t->bus_freq_hz = 100000;
1538
1539         ret = device_property_read_u32(dev, "i2c-scl-rising-time-ns", &t->scl_rise_ns);
1540         if (ret && use_defaults) {
1541                 if (t->bus_freq_hz <= 100000)
1542                         t->scl_rise_ns = 1000;
1543                 else if (t->bus_freq_hz <= 400000)
1544                         t->scl_rise_ns = 300;
1545                 else
1546                         t->scl_rise_ns = 120;
1547         }
1548
1549         ret = device_property_read_u32(dev, "i2c-scl-falling-time-ns", &t->scl_fall_ns);
1550         if (ret && use_defaults) {
1551                 if (t->bus_freq_hz <= 400000)
1552                         t->scl_fall_ns = 300;
1553                 else
1554                         t->scl_fall_ns = 120;
1555         }
1556
1557         device_property_read_u32(dev, "i2c-scl-internal-delay-ns", &t->scl_int_delay_ns);
1558
1559         ret = device_property_read_u32(dev, "i2c-sda-falling-time-ns", &t->sda_fall_ns);
1560         if (ret && use_defaults)
1561                 t->sda_fall_ns = t->scl_fall_ns;
1562 }
1563 EXPORT_SYMBOL_GPL(i2c_parse_fw_timings);
1564
1565 /* ------------------------------------------------------------------------- */
1566
1567 int i2c_for_each_dev(void *data, int (*fn)(struct device *, void *))
1568 {
1569         int res;
1570
1571         mutex_lock(&core_lock);
1572         res = bus_for_each_dev(&i2c_bus_type, NULL, data, fn);
1573         mutex_unlock(&core_lock);
1574
1575         return res;
1576 }
1577 EXPORT_SYMBOL_GPL(i2c_for_each_dev);
1578
1579 static int __process_new_driver(struct device *dev, void *data)
1580 {
1581         if (dev->type != &i2c_adapter_type)
1582                 return 0;
1583         return i2c_do_add_adapter(data, to_i2c_adapter(dev));
1584 }
1585
1586 /*
1587  * An i2c_driver is used with one or more i2c_client (device) nodes to access
1588  * i2c slave chips, on a bus instance associated with some i2c_adapter.
1589  */
1590
1591 int i2c_register_driver(struct module *owner, struct i2c_driver *driver)
1592 {
1593         int res;
1594
1595         /* Can't register until after driver model init */
1596         if (WARN_ON(!is_registered))
1597                 return -EAGAIN;
1598
1599         /* add the driver to the list of i2c drivers in the driver core */
1600         driver->driver.owner = owner;
1601         driver->driver.bus = &i2c_bus_type;
1602         INIT_LIST_HEAD(&driver->clients);
1603
1604         /* When registration returns, the driver core
1605          * will have called probe() for all matching-but-unbound devices.
1606          */
1607         res = driver_register(&driver->driver);
1608         if (res)
1609                 return res;
1610
1611         pr_debug("driver [%s] registered\n", driver->driver.name);
1612
1613         /* Walk the adapters that are already present */
1614         i2c_for_each_dev(driver, __process_new_driver);
1615
1616         return 0;
1617 }
1618 EXPORT_SYMBOL(i2c_register_driver);
1619
1620 static int __process_removed_driver(struct device *dev, void *data)
1621 {
1622         if (dev->type == &i2c_adapter_type)
1623                 i2c_do_del_adapter(data, to_i2c_adapter(dev));
1624         return 0;
1625 }
1626
1627 /**
1628  * i2c_del_driver - unregister I2C driver
1629  * @driver: the driver being unregistered
1630  * Context: can sleep
1631  */
1632 void i2c_del_driver(struct i2c_driver *driver)
1633 {
1634         i2c_for_each_dev(driver, __process_removed_driver);
1635
1636         driver_unregister(&driver->driver);
1637         pr_debug("driver [%s] unregistered\n", driver->driver.name);
1638 }
1639 EXPORT_SYMBOL(i2c_del_driver);
1640
1641 /* ------------------------------------------------------------------------- */
1642
1643 /**
1644  * i2c_use_client - increments the reference count of the i2c client structure
1645  * @client: the client being referenced
1646  *
1647  * Each live reference to a client should be refcounted. The driver model does
1648  * that automatically as part of driver binding, so that most drivers don't
1649  * need to do this explicitly: they hold a reference until they're unbound
1650  * from the device.
1651  *
1652  * A pointer to the client with the incremented reference counter is returned.
1653  */
1654 struct i2c_client *i2c_use_client(struct i2c_client *client)
1655 {
1656         if (client && get_device(&client->dev))
1657                 return client;
1658         return NULL;
1659 }
1660 EXPORT_SYMBOL(i2c_use_client);
1661
1662 /**
1663  * i2c_release_client - release a use of the i2c client structure
1664  * @client: the client being no longer referenced
1665  *
1666  * Must be called when a user of a client is finished with it.
1667  */
1668 void i2c_release_client(struct i2c_client *client)
1669 {
1670         if (client)
1671                 put_device(&client->dev);
1672 }
1673 EXPORT_SYMBOL(i2c_release_client);
1674
1675 struct i2c_cmd_arg {
1676         unsigned        cmd;
1677         void            *arg;
1678 };
1679
1680 static int i2c_cmd(struct device *dev, void *_arg)
1681 {
1682         struct i2c_client       *client = i2c_verify_client(dev);
1683         struct i2c_cmd_arg      *arg = _arg;
1684         struct i2c_driver       *driver;
1685
1686         if (!client || !client->dev.driver)
1687                 return 0;
1688
1689         driver = to_i2c_driver(client->dev.driver);
1690         if (driver->command)
1691                 driver->command(client, arg->cmd, arg->arg);
1692         return 0;
1693 }
1694
1695 void i2c_clients_command(struct i2c_adapter *adap, unsigned int cmd, void *arg)
1696 {
1697         struct i2c_cmd_arg      cmd_arg;
1698
1699         cmd_arg.cmd = cmd;
1700         cmd_arg.arg = arg;
1701         device_for_each_child(&adap->dev, &cmd_arg, i2c_cmd);
1702 }
1703 EXPORT_SYMBOL(i2c_clients_command);
1704
1705 static int __init i2c_init(void)
1706 {
1707         int retval;
1708
1709         retval = of_alias_get_highest_id("i2c");
1710
1711         down_write(&__i2c_board_lock);
1712         if (retval >= __i2c_first_dynamic_bus_num)
1713                 __i2c_first_dynamic_bus_num = retval + 1;
1714         up_write(&__i2c_board_lock);
1715
1716         retval = bus_register(&i2c_bus_type);
1717         if (retval)
1718                 return retval;
1719
1720         is_registered = true;
1721
1722 #ifdef CONFIG_I2C_COMPAT
1723         i2c_adapter_compat_class = class_compat_register("i2c-adapter");
1724         if (!i2c_adapter_compat_class) {
1725                 retval = -ENOMEM;
1726                 goto bus_err;
1727         }
1728 #endif
1729         retval = i2c_add_driver(&dummy_driver);
1730         if (retval)
1731                 goto class_err;
1732
1733         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1734                 WARN_ON(of_reconfig_notifier_register(&i2c_of_notifier));
1735         if (IS_ENABLED(CONFIG_ACPI))
1736                 WARN_ON(acpi_reconfig_notifier_register(&i2c_acpi_notifier));
1737
1738         return 0;
1739
1740 class_err:
1741 #ifdef CONFIG_I2C_COMPAT
1742         class_compat_unregister(i2c_adapter_compat_class);
1743 bus_err:
1744 #endif
1745         is_registered = false;
1746         bus_unregister(&i2c_bus_type);
1747         return retval;
1748 }
1749
1750 static void __exit i2c_exit(void)
1751 {
1752         if (IS_ENABLED(CONFIG_ACPI))
1753                 WARN_ON(acpi_reconfig_notifier_unregister(&i2c_acpi_notifier));
1754         if (IS_ENABLED(CONFIG_OF_DYNAMIC))
1755                 WARN_ON(of_reconfig_notifier_unregister(&i2c_of_notifier));
1756         i2c_del_driver(&dummy_driver);
1757 #ifdef CONFIG_I2C_COMPAT
1758         class_compat_unregister(i2c_adapter_compat_class);
1759 #endif
1760         bus_unregister(&i2c_bus_type);
1761         tracepoint_synchronize_unregister();
1762 }
1763
1764 /* We must initialize early, because some subsystems register i2c drivers
1765  * in subsys_initcall() code, but are linked (and initialized) before i2c.
1766  */
1767 postcore_initcall(i2c_init);
1768 module_exit(i2c_exit);
1769
1770 /* ----------------------------------------------------
1771  * the functional interface to the i2c busses.
1772  * ----------------------------------------------------
1773  */
1774
1775 /* Check if val is exceeding the quirk IFF quirk is non 0 */
1776 #define i2c_quirk_exceeded(val, quirk) ((quirk) && ((val) > (quirk)))
1777
1778 static int i2c_quirk_error(struct i2c_adapter *adap, struct i2c_msg *msg, char *err_msg)
1779 {
1780         dev_err_ratelimited(&adap->dev, "adapter quirk: %s (addr 0x%04x, size %u, %s)\n",
1781                             err_msg, msg->addr, msg->len,
1782                             msg->flags & I2C_M_RD ? "read" : "write");
1783         return -EOPNOTSUPP;
1784 }
1785
1786 static int i2c_check_for_quirks(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1787 {
1788         const struct i2c_adapter_quirks *q = adap->quirks;
1789         int max_num = q->max_num_msgs, i;
1790         bool do_len_check = true;
1791
1792         if (q->flags & I2C_AQ_COMB) {
1793                 max_num = 2;
1794
1795                 /* special checks for combined messages */
1796                 if (num == 2) {
1797                         if (q->flags & I2C_AQ_COMB_WRITE_FIRST && msgs[0].flags & I2C_M_RD)
1798                                 return i2c_quirk_error(adap, &msgs[0], "1st comb msg must be write");
1799
1800                         if (q->flags & I2C_AQ_COMB_READ_SECOND && !(msgs[1].flags & I2C_M_RD))
1801                                 return i2c_quirk_error(adap, &msgs[1], "2nd comb msg must be read");
1802
1803                         if (q->flags & I2C_AQ_COMB_SAME_ADDR && msgs[0].addr != msgs[1].addr)
1804                                 return i2c_quirk_error(adap, &msgs[0], "comb msg only to same addr");
1805
1806                         if (i2c_quirk_exceeded(msgs[0].len, q->max_comb_1st_msg_len))
1807                                 return i2c_quirk_error(adap, &msgs[0], "msg too long");
1808
1809                         if (i2c_quirk_exceeded(msgs[1].len, q->max_comb_2nd_msg_len))
1810                                 return i2c_quirk_error(adap, &msgs[1], "msg too long");
1811
1812                         do_len_check = false;
1813                 }
1814         }
1815
1816         if (i2c_quirk_exceeded(num, max_num))
1817                 return i2c_quirk_error(adap, &msgs[0], "too many messages");
1818
1819         for (i = 0; i < num; i++) {
1820                 u16 len = msgs[i].len;
1821
1822                 if (msgs[i].flags & I2C_M_RD) {
1823                         if (do_len_check && i2c_quirk_exceeded(len, q->max_read_len))
1824                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1825                 } else {
1826                         if (do_len_check && i2c_quirk_exceeded(len, q->max_write_len))
1827                                 return i2c_quirk_error(adap, &msgs[i], "msg too long");
1828                 }
1829         }
1830
1831         return 0;
1832 }
1833
1834 /**
1835  * __i2c_transfer - unlocked flavor of i2c_transfer
1836  * @adap: Handle to I2C bus
1837  * @msgs: One or more messages to execute before STOP is issued to
1838  *      terminate the operation; each message begins with a START.
1839  * @num: Number of messages to be executed.
1840  *
1841  * Returns negative errno, else the number of messages executed.
1842  *
1843  * Adapter lock must be held when calling this function. No debug logging
1844  * takes place. adap->algo->master_xfer existence isn't checked.
1845  */
1846 int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1847 {
1848         unsigned long orig_jiffies;
1849         int ret, try;
1850
1851         if (adap->quirks && i2c_check_for_quirks(adap, msgs, num))
1852                 return -EOPNOTSUPP;
1853
1854         /* i2c_trace_msg gets enabled when tracepoint i2c_transfer gets
1855          * enabled.  This is an efficient way of keeping the for-loop from
1856          * being executed when not needed.
1857          */
1858         if (static_key_false(&i2c_trace_msg)) {
1859                 int i;
1860                 for (i = 0; i < num; i++)
1861                         if (msgs[i].flags & I2C_M_RD)
1862                                 trace_i2c_read(adap, &msgs[i], i);
1863                         else
1864                                 trace_i2c_write(adap, &msgs[i], i);
1865         }
1866
1867         /* Retry automatically on arbitration loss */
1868         orig_jiffies = jiffies;
1869         for (ret = 0, try = 0; try <= adap->retries; try++) {
1870                 ret = adap->algo->master_xfer(adap, msgs, num);
1871                 if (ret != -EAGAIN)
1872                         break;
1873                 if (time_after(jiffies, orig_jiffies + adap->timeout))
1874                         break;
1875         }
1876
1877         if (static_key_false(&i2c_trace_msg)) {
1878                 int i;
1879                 for (i = 0; i < ret; i++)
1880                         if (msgs[i].flags & I2C_M_RD)
1881                                 trace_i2c_reply(adap, &msgs[i], i);
1882                 trace_i2c_result(adap, i, ret);
1883         }
1884
1885         return ret;
1886 }
1887 EXPORT_SYMBOL(__i2c_transfer);
1888
1889 /**
1890  * i2c_transfer - execute a single or combined I2C message
1891  * @adap: Handle to I2C bus
1892  * @msgs: One or more messages to execute before STOP is issued to
1893  *      terminate the operation; each message begins with a START.
1894  * @num: Number of messages to be executed.
1895  *
1896  * Returns negative errno, else the number of messages executed.
1897  *
1898  * Note that there is no requirement that each message be sent to
1899  * the same slave address, although that is the most common model.
1900  */
1901 int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
1902 {
1903         int ret;
1904
1905         /* REVISIT the fault reporting model here is weak:
1906          *
1907          *  - When we get an error after receiving N bytes from a slave,
1908          *    there is no way to report "N".
1909          *
1910          *  - When we get a NAK after transmitting N bytes to a slave,
1911          *    there is no way to report "N" ... or to let the master
1912          *    continue executing the rest of this combined message, if
1913          *    that's the appropriate response.
1914          *
1915          *  - When for example "num" is two and we successfully complete
1916          *    the first message but get an error part way through the
1917          *    second, it's unclear whether that should be reported as
1918          *    one (discarding status on the second message) or errno
1919          *    (discarding status on the first one).
1920          */
1921
1922         if (adap->algo->master_xfer) {
1923 #ifdef DEBUG
1924                 for (ret = 0; ret < num; ret++) {
1925                         dev_dbg(&adap->dev,
1926                                 "master_xfer[%d] %c, addr=0x%02x, len=%d%s\n",
1927                                 ret, (msgs[ret].flags & I2C_M_RD) ? 'R' : 'W',
1928                                 msgs[ret].addr, msgs[ret].len,
1929                                 (msgs[ret].flags & I2C_M_RECV_LEN) ? "+" : "");
1930                 }
1931 #endif
1932
1933                 if (in_atomic() || irqs_disabled()) {
1934                         ret = i2c_trylock_bus(adap, I2C_LOCK_SEGMENT);
1935                         if (!ret)
1936                                 /* I2C activity is ongoing. */
1937                                 return -EAGAIN;
1938                 } else {
1939                         i2c_lock_bus(adap, I2C_LOCK_SEGMENT);
1940                 }
1941
1942                 ret = __i2c_transfer(adap, msgs, num);
1943                 i2c_unlock_bus(adap, I2C_LOCK_SEGMENT);
1944
1945                 return ret;
1946         } else {
1947                 dev_dbg(&adap->dev, "I2C level transfers not supported\n");
1948                 return -EOPNOTSUPP;
1949         }
1950 }
1951 EXPORT_SYMBOL(i2c_transfer);
1952
1953 /**
1954  * i2c_master_send - issue a single I2C message in master transmit mode
1955  * @client: Handle to slave device
1956  * @buf: Data that will be written to the slave
1957  * @count: How many bytes to write, must be less than 64k since msg.len is u16
1958  *
1959  * Returns negative errno, or else the number of bytes written.
1960  */
1961 int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
1962 {
1963         int ret;
1964         struct i2c_adapter *adap = client->adapter;
1965         struct i2c_msg msg;
1966
1967         msg.addr = client->addr;
1968         msg.flags = client->flags & I2C_M_TEN;
1969         msg.len = count;
1970         msg.buf = (char *)buf;
1971
1972         ret = i2c_transfer(adap, &msg, 1);
1973
1974         /*
1975          * If everything went ok (i.e. 1 msg transmitted), return #bytes
1976          * transmitted, else error code.
1977          */
1978         return (ret == 1) ? count : ret;
1979 }
1980 EXPORT_SYMBOL(i2c_master_send);
1981
1982 /**
1983  * i2c_master_recv - issue a single I2C message in master receive mode
1984  * @client: Handle to slave device
1985  * @buf: Where to store data read from slave
1986  * @count: How many bytes to read, must be less than 64k since msg.len is u16
1987  *
1988  * Returns negative errno, or else the number of bytes read.
1989  */
1990 int i2c_master_recv(const struct i2c_client *client, char *buf, int count)
1991 {
1992         struct i2c_adapter *adap = client->adapter;
1993         struct i2c_msg msg;
1994         int ret;
1995
1996         msg.addr = client->addr;
1997         msg.flags = client->flags & I2C_M_TEN;
1998         msg.flags |= I2C_M_RD;
1999         msg.len = count;
2000         msg.buf = buf;
2001
2002         ret = i2c_transfer(adap, &msg, 1);
2003
2004         /*
2005          * If everything went ok (i.e. 1 msg received), return #bytes received,
2006          * else error code.
2007          */
2008         return (ret == 1) ? count : ret;
2009 }
2010 EXPORT_SYMBOL(i2c_master_recv);
2011
2012 /* ----------------------------------------------------
2013  * the i2c address scanning function
2014  * Will not work for 10-bit addresses!
2015  * ----------------------------------------------------
2016  */
2017
2018 /*
2019  * Legacy default probe function, mostly relevant for SMBus. The default
2020  * probe method is a quick write, but it is known to corrupt the 24RF08
2021  * EEPROMs due to a state machine bug, and could also irreversibly
2022  * write-protect some EEPROMs, so for address ranges 0x30-0x37 and 0x50-0x5f,
2023  * we use a short byte read instead. Also, some bus drivers don't implement
2024  * quick write, so we fallback to a byte read in that case too.
2025  * On x86, there is another special case for FSC hardware monitoring chips,
2026  * which want regular byte reads (address 0x73.) Fortunately, these are the
2027  * only known chips using this I2C address on PC hardware.
2028  * Returns 1 if probe succeeded, 0 if not.
2029  */
2030 static int i2c_default_probe(struct i2c_adapter *adap, unsigned short addr)
2031 {
2032         int err;
2033         union i2c_smbus_data dummy;
2034
2035 #ifdef CONFIG_X86
2036         if (addr == 0x73 && (adap->class & I2C_CLASS_HWMON)
2037          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE_DATA))
2038                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2039                                      I2C_SMBUS_BYTE_DATA, &dummy);
2040         else
2041 #endif
2042         if (!((addr & ~0x07) == 0x30 || (addr & ~0x0f) == 0x50)
2043          && i2c_check_functionality(adap, I2C_FUNC_SMBUS_QUICK))
2044                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_WRITE, 0,
2045                                      I2C_SMBUS_QUICK, NULL);
2046         else if (i2c_check_functionality(adap, I2C_FUNC_SMBUS_READ_BYTE))
2047                 err = i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2048                                      I2C_SMBUS_BYTE, &dummy);
2049         else {
2050                 dev_warn(&adap->dev, "No suitable probing method supported for address 0x%02X\n",
2051                          addr);
2052                 err = -EOPNOTSUPP;
2053         }
2054
2055         return err >= 0;
2056 }
2057
2058 static int i2c_detect_address(struct i2c_client *temp_client,
2059                               struct i2c_driver *driver)
2060 {
2061         struct i2c_board_info info;
2062         struct i2c_adapter *adapter = temp_client->adapter;
2063         int addr = temp_client->addr;
2064         int err;
2065
2066         /* Make sure the address is valid */
2067         err = i2c_check_7bit_addr_validity_strict(addr);
2068         if (err) {
2069                 dev_warn(&adapter->dev, "Invalid probe address 0x%02x\n",
2070                          addr);
2071                 return err;
2072         }
2073
2074         /* Skip if already in use (7 bit, no need to encode flags) */
2075         if (i2c_check_addr_busy(adapter, addr))
2076                 return 0;
2077
2078         /* Make sure there is something at this address */
2079         if (!i2c_default_probe(adapter, addr))
2080                 return 0;
2081
2082         /* Finally call the custom detection function */
2083         memset(&info, 0, sizeof(struct i2c_board_info));
2084         info.addr = addr;
2085         err = driver->detect(temp_client, &info);
2086         if (err) {
2087                 /* -ENODEV is returned if the detection fails. We catch it
2088                    here as this isn't an error. */
2089                 return err == -ENODEV ? 0 : err;
2090         }
2091
2092         /* Consistency check */
2093         if (info.type[0] == '\0') {
2094                 dev_err(&adapter->dev,
2095                         "%s detection function provided no name for 0x%x\n",
2096                         driver->driver.name, addr);
2097         } else {
2098                 struct i2c_client *client;
2099
2100                 /* Detection succeeded, instantiate the device */
2101                 if (adapter->class & I2C_CLASS_DEPRECATED)
2102                         dev_warn(&adapter->dev,
2103                                 "This adapter will soon drop class based instantiation of devices. "
2104                                 "Please make sure client 0x%02x gets instantiated by other means. "
2105                                 "Check 'Documentation/i2c/instantiating-devices' for details.\n",
2106                                 info.addr);
2107
2108                 dev_dbg(&adapter->dev, "Creating %s at 0x%02x\n",
2109                         info.type, info.addr);
2110                 client = i2c_new_device(adapter, &info);
2111                 if (client)
2112                         list_add_tail(&client->detected, &driver->clients);
2113                 else
2114                         dev_err(&adapter->dev, "Failed creating %s at 0x%02x\n",
2115                                 info.type, info.addr);
2116         }
2117         return 0;
2118 }
2119
2120 static int i2c_detect(struct i2c_adapter *adapter, struct i2c_driver *driver)
2121 {
2122         const unsigned short *address_list;
2123         struct i2c_client *temp_client;
2124         int i, err = 0;
2125         int adap_id = i2c_adapter_id(adapter);
2126
2127         address_list = driver->address_list;
2128         if (!driver->detect || !address_list)
2129                 return 0;
2130
2131         /* Warn that the adapter lost class based instantiation */
2132         if (adapter->class == I2C_CLASS_DEPRECATED) {
2133                 dev_dbg(&adapter->dev,
2134                         "This adapter dropped support for I2C classes and won't auto-detect %s devices anymore. "
2135                         "If you need it, check 'Documentation/i2c/instantiating-devices' for alternatives.\n",
2136                         driver->driver.name);
2137                 return 0;
2138         }
2139
2140         /* Stop here if the classes do not match */
2141         if (!(adapter->class & driver->class))
2142                 return 0;
2143
2144         /* Set up a temporary client to help detect callback */
2145         temp_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
2146         if (!temp_client)
2147                 return -ENOMEM;
2148         temp_client->adapter = adapter;
2149
2150         for (i = 0; address_list[i] != I2C_CLIENT_END; i += 1) {
2151                 dev_dbg(&adapter->dev,
2152                         "found normal entry for adapter %d, addr 0x%02x\n",
2153                         adap_id, address_list[i]);
2154                 temp_client->addr = address_list[i];
2155                 err = i2c_detect_address(temp_client, driver);
2156                 if (unlikely(err))
2157                         break;
2158         }
2159
2160         kfree(temp_client);
2161         return err;
2162 }
2163
2164 int i2c_probe_func_quick_read(struct i2c_adapter *adap, unsigned short addr)
2165 {
2166         return i2c_smbus_xfer(adap, addr, 0, I2C_SMBUS_READ, 0,
2167                               I2C_SMBUS_QUICK, NULL) >= 0;
2168 }
2169 EXPORT_SYMBOL_GPL(i2c_probe_func_quick_read);
2170
2171 struct i2c_client *
2172 i2c_new_probed_device(struct i2c_adapter *adap,
2173                       struct i2c_board_info *info,
2174                       unsigned short const *addr_list,
2175                       int (*probe)(struct i2c_adapter *, unsigned short addr))
2176 {
2177         int i;
2178
2179         if (!probe)
2180                 probe = i2c_default_probe;
2181
2182         for (i = 0; addr_list[i] != I2C_CLIENT_END; i++) {
2183                 /* Check address validity */
2184                 if (i2c_check_7bit_addr_validity_strict(addr_list[i]) < 0) {
2185                         dev_warn(&adap->dev, "Invalid 7-bit address 0x%02x\n",
2186                                  addr_list[i]);
2187                         continue;
2188                 }
2189
2190                 /* Check address availability (7 bit, no need to encode flags) */
2191                 if (i2c_check_addr_busy(adap, addr_list[i])) {
2192                         dev_dbg(&adap->dev,
2193                                 "Address 0x%02x already in use, not probing\n",
2194                                 addr_list[i]);
2195                         continue;
2196                 }
2197
2198                 /* Test address responsiveness */
2199                 if (probe(adap, addr_list[i]))
2200                         break;
2201         }
2202
2203         if (addr_list[i] == I2C_CLIENT_END) {
2204                 dev_dbg(&adap->dev, "Probing failed, no device found\n");
2205                 return NULL;
2206         }
2207
2208         info->addr = addr_list[i];
2209         return i2c_new_device(adap, info);
2210 }
2211 EXPORT_SYMBOL_GPL(i2c_new_probed_device);
2212
2213 struct i2c_adapter *i2c_get_adapter(int nr)
2214 {
2215         struct i2c_adapter *adapter;
2216
2217         mutex_lock(&core_lock);
2218         adapter = idr_find(&i2c_adapter_idr, nr);
2219         if (!adapter)
2220                 goto exit;
2221
2222         if (try_module_get(adapter->owner))
2223                 get_device(&adapter->dev);
2224         else
2225                 adapter = NULL;
2226
2227  exit:
2228         mutex_unlock(&core_lock);
2229         return adapter;
2230 }
2231 EXPORT_SYMBOL(i2c_get_adapter);
2232
2233 void i2c_put_adapter(struct i2c_adapter *adap)
2234 {
2235         if (!adap)
2236                 return;
2237
2238         put_device(&adap->dev);
2239         module_put(adap->owner);
2240 }
2241 EXPORT_SYMBOL(i2c_put_adapter);
2242
2243 MODULE_AUTHOR("Simon G. Vogl <simon@tk.uni-linz.ac.at>");
2244 MODULE_DESCRIPTION("I2C-Bus main module");
2245 MODULE_LICENSE("GPL");